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RATIONALE: The 5-HT transporter (5-HTT) is implicated in the regulation of appetite. Expression of the 5-HTT varies in the human population, and this variation may determine both individual differences in feeding and abnormal feeding behaviours such as eating disorders. OBJECTIVES: The effects of 5-HTT expression on feeding and satiety were examined in a transgenic mouse model of 5-HTT overexpression. MATERIALS AND METHODS: We measured free-feeding food intake and observed the behavioural satiety sequence (BSS) after food deprivation in mice at baseline and after administration of the anorectic drug fenfluramine. RESULTS: 5-HTT overexpressing mice were both lighter and shorter than their wildtype littermates. Despite this size difference, food intake by transgenic and wildtype mice did not differ. There was no effect of genotype on the BSS or on food intake during the test at baseline. Increasing doses of fenfluramine reduced food intake in a similar manner in both transgenic and wildtype mice. After 0.3 and 1 mg/kg fenfluramine, the temporal pattern of the BSS was the same for both groups, whereas 3 and 10 mg/kg fenfluramine disrupted the BSS. In transgenic mice, this disruption was evident at the 3 mg/kg dose, while in wildtypes, it emerged only at the 10-mg/kg dose. CONCLUSION: These data suggest that overexpression of the 5-HTT does not lead to alterations in feeding or satiety in food-deprived mice but does increase the occurrence of other non-feeding behaviours in response to the 5-HT releasing agent fenfluramine.

Previous studies have identified a positive relationship between dietary restraint and alcohol use. However, it is unclear whether heavier drinking is associated with higher dietary restraint per se, or restraint combined with a tendency towards disinhibition. The aim of the present study was to examine alcohol use behaviours in women classified using both restraint and disinhibition scores. Forty-four young female social drinkers gave self-reported measures of their drinking behaviour, including frequency and quantity of alcohol consumed and frequency of drunkenness and binge drinking. Attentional bias for alcohol-related stimuli was also assessed using a dot probe detection task. Finally, the Temptation and Restraint Inventory was used to investigate whether preoccupation with drinking might underlie the relationship between dietary and drinking behaviours. Women classified as both highly restrained and disinhibited tended to report more episodes of drunkenness, showed an attentional bias for alcohol-related words, and had greater cognitive preoccupation with drinking compared to other dietary groups. These data suggest that a tendency towards overeating (disinhibition) combined with attempts at restriction is associated with increased alcohol use behaviours, perhaps due to a greater preoccupation with alcohol.

The cannabinoid receptor agonists delta9-tetrahydrocannabinol (delta9-THC) and HU-210 were compared in terms of their effects on: (1) progressive ratio (PR) responding for food, and (2) free food intake. In the first experiment, food-deprived Wistar rats were trained on a time-constrained (60 min) PR-5 schedule for food reinforcement, in which the response requirement incremented by five lever presses for each successive reinforcer. One group of rats received vehicle, 0.5, 1 or 3 mg/kg delta9-THC (i.p.), and three other groups received HU-210 (i.p.) at three different dose ranges, spanning 0.001-0.1 mg/kg. In the second experiment, the effects of the two drugs on free food intake were tested in a separate group of non-deprived rats. For PR responding, delta9-THC significantly increased the break point (final ratio completed) and the total number of lever presses emitted. The same drug also significantly increased free food intake. However, the effects of HU-210 were quite different: it did not alter PR responding at any dose; instead, its only significant effect was to reduce free food intake at 0.06 mg/kg. These data suggest that increased motivation to obtain food might underlie the hyperphagic effects of delta9-THC. However, the synthetic agonist HU-210 has different effects: it only acts to reduce feeding behaviour, an outcome that probably reflects non-specific behavioural disruption. These findings suggest important differences between the two CB1 receptor agonists in terms of their pharmacological effects.

Previous research has indicated that flavor-flavor learning is impaired in restrained eaters. In Experiment 1 we sought to extend this finding using a larger sample and a more comprehensive assessment of dietary behavior. Participants (N=90, including 30 current dieters) sampled three novel flavors (CSs), each on 10 separate occasions, in a randomized order. Each flavor was paired with chocolate (US) either 10%, 50%, or 90% of the time. We then assessed liking for the three CSs and asked participants to complete the DEBQ-restraint and TFEQ-disinhibition sub-scales. After these CS-US parings, restrained eaters tended to prefer the 10% paired flavor whereas unrestrained eaters tended to prefer the 90% paired flavor. Differential CS liking was not evident in dieters and it was not predicted by disinhibition. Using a similar methodology, in Experiment 2 (N=76) we assessed evaluative change following picture-sweet pairings. Relative to the other CSs, the restrained eaters reported a greater increase in their liking for the 10% paired CS and the unrestrained eaters reported a greater increase in their liking for the 90% paired CS. We also discovered that evaluative change is related to the level of US devaluation that takes place during conditioning. Evidence that a sweet US can bring about a decrease in liking has not been reported previously. One interpretation is that negative beliefs and attitudes can contaminate the representation of the US during training.

The aim of this study was to investigate, for the first time, the effects of a centrally active benzodiazepine receptor agonist, midazolam maleate, on the microstructure of licking responses for a range of sodium chloride (NaCl) solutions in mildly water-deprived male rats. Doses of midazolam were chosen (0.3-3.0 mg/kg. i.p.) which have been characterised in studies of licking responses for several different kinds of nutrients. NaCl concentrations (0.075 M-0.45 M) were chosen to cover a range of taste preferences and acceptability. A brief-contact testing session was employed to focus on the initial determinants of licking responses (i.e. taste palatability), and to minimise any contribution of post-ingestional effects. The results indicate the midazolam significantly increased the total number of licks recorded across all salt concentrations, but that it had no effect on the number of bouts of licking. Instead, midazolam specifically enhanced the mean duration of licking bouts, an effect that was most evident at the weaker but more acceptable NaCl concentrations (0.075 M and 0.15 M). In addition, midazolam diminished the intrabout rate of licking across all salt concentrations. These results confirm that benzodiazepines can exert a specific pattern of effects on the microstructure of licking for salt solutions. They are discussed in terms of the oropharyngeal stimulation controlling intake and the palatability or "liking" hypothesis for the effects of benzodiazepines on taste stimuli, and indicate that the hypothesis is applicable to salt solution ingestive behaviour.

The motivational mechanisms underlying the effects of systemic administration of the GABA-B agonist baclofen on feeding were examined using a runway. Food-deprived male hooded Lister rats were trained to traverse a runway for food reinforcement. Baclofen (1 mg/kg i.p.) significantly increased food intake and this was most evident on the final two blocks of testing. The 2 mg/kg dose of baclofen increased running speed without significantly altering intake. At the highest dose tested (4 mg/kg), no significant effects on either consummatory or appetitive measures were observed. These data suggest that low doses of baclofen enhance the consummatory phase of ingestion by attenuating the natural signals associated with onset of satiation. The data also suggest that baclofen has complex effects on appetitive behaviour that may interfere with its effects on consumption.

The effect of being reminded of a recent eating episode on subsequent food intake was examined in unrestrained eaters. In Experiment 1, female participants were exposed to a "lunch cue" (in which they were asked to think about what they had eaten for lunch), or "no cue" (free thought condition), for 5 min prior to eating. Participants ate less following exposure to the "lunch cue" than the "no cue" condition. In Experiment 2, food intake was measured following exposure to either a "lunch today" cue, "lunch yesterday" cue or "no cue" condition. Intake in the "lunch today" condition was suppressed relative to both the "lunch yesterday" and "no cue" condition. Subjective ratings of hunger, fullness, and desire to eat did not vary as a function of cue type in either Experiment 1 or Experiment 2. These results are consistent with the suggestion that memory of recent eating is an important cognitive factor influencing food intake.

Rationale. Central cannabinoid systems have been implicated in appetite control through the respective hyperphagic and anorectic actions of CB1 agonists and antagonists. The motivational changes underlying these actions remain to be determined, but may involve alterations to food palatability. Objectives. The mode of action of cannabinoids on ingestion was investigated by examining the effects of exogenous and endogenous agonists, and a selective CB1 receptor antagonist, on licking microstructure in rats ingesting a palatable sucrose solution. Methods. Microstructural analyses of licking for a 10% sucrose solution was performed over a range of agonist and antagonist doses administered to non-deprived, male Lister hooded rats. Results. Δ9-tetrahydrocannabinol (0.5, 1 and 3 mg/kg) and anandamide (1 mg/kg and 3 mg/kg) significantly increased total number of licks. This was primarily due to an increase in bout duration rather than bout number. There was a non-significant increase in total licks following administration of 2-arachidonoyl glycerol (0.2, 1.0 and 2.0 mg/kg), whereas administration of the CB1 antagonist SR141716 (1 mg/kg and 3 mg/kg) significantly decreased total licks. All drugs, with the exception of anandamide, significantly decreased the intra-bout lick rate. An exponential function fitted to the cumulative lick rate curves for each drug revealed that all compounds altered the asymptote of this function without having any marked effects on the exponent. Conclusions. These data are consistent with endocannabinoid involvement in the mediation of food palatability.

Flavour preference learning in 21 restrained and 21 unrestrained females was explored using an evaluative conditioning paradigm. Each participant was exposed to an adapted version of the procedure used by Johnsrude et al ., (1999, Learning & Motivation 30 , 250–264). During conditioning, participants sampled 10 instances each of three novel flavours presented in a semi-randomized order. After sampling a flavour they were instructed to eat a sweet according to three different flavour-reinforcement contingencies. One flavour was accompanied by a sweet on 90% of trials and was presented alone on 10% of the trials, while the remaining flavours were rewarded at ratios 50% : 50% and 10% : 90%, respectively. The conditioning phase occurred in conjunction with a counting task requiring continuous use of working memory, and was immediately followed by the participants making hedonic ratings of each flavour. Very few participants showed awareness of the purpose of the experiment or the specific reward contingencies. Despite this, the ratings given by the unrestrained eaters were highly correlated with the reward ratio experienced during conditioning. In contrast, restrained eaters exhibited no evidence for evaluative learning. These findings may explain the equivocal nature of results from previous studies of positive flavour-flavour learning (FFL) and may offer a novel theoretical context within which to study dietary restraint.

Table 2 Study 2: Expected liking ratings by food type and food rated. Baseline expected liking (0–10 score) Mismatch between actual and expected liking (0–10 score) Change in expected (0–10 score) Disappointing consumption experience Infrequently eaten food 6.4 (1.8) 2.3 (1.3) 1.8 (1.6) Frequently eaten food 8.6 (1.0) 2.2 (1.7) 0.7 (1.3) No consumption experience Infrequently eaten food 5.4 (3.0) – 0.6 (1.6) Frequently eaten food 8.3 (1.4) – 0.3 (0.8) Not disappointing consumption experience Infrequently eaten food 5.7 (2.7) 0.2 (0.8) 0.1 (0.9) Frequently eaten food 7.4 (2.7) 0.3 (0.3) 0.4 (1.3)

Numerous studies have covertly examined eating behaviour in the laboratory with a Universal Eating Monitor (UEM). However, using this method, participants might behave in a way that disrupts the recording of their eating behaviour (e.g. accidentally leaning on the hidden scales). To date, no study has directly investigated whether a covert approach is necessary and whether awareness of a UEM affects eating behaviour. To assess this factor, we recruited participants to eat an ad-libitum lunch of pasta followed by an ad-libitum snack of cookies. Participants were either made explicitly aware of the UEM and informed that it would be recording their food intake (aware condition), or were not told about the UEM (non-aware condition). Participants in the non-aware condition were questioned at the end of the study to confirm whether they were aware or non-aware during their session. Analysis of various measures of eating (e.g. total amount eaten, duration of eating) and eating microstructure (e.g. number of mouthfuls eaten, eating rate) showed no significant difference between aware or non-aware groups. We conclude that awareness of the UEM does not significantly affect eating behaviour, and that a covert approach is not required.

Evidence suggests that food memories may be influenced by eating habits. However, the relationship between restraint, emotional, and external eating and food memories has yet to be thoroughly investigated or compared to visual memory more generally. Here we investigated the relationship between scores on the Dutch Eating Behaviour Questionnaire (DEBQ), snack recall, and visual memory. 100 female undergraduate students participated, with a mean age of 18.8 years, and a mean BMI of 22.3. Participants consumed a snack of 7 different coloured jelly beans, followed by either an immediate snack recall or a delayed recall. Recall required participants to list the colour order in which they consumed each Jelly Bean. Both groups then completed two computerized neuropsychological tests of visual memory. The Food Preoccupation Questionnaire was also completed to test for mediation effects. Hunger at baseline and BMI were not related to snack recall accuracy. Linear regression showed that restraint was a significant predictor of recall accuracy (higher restraint was associated with better recall) and recall accuracy was also related to food preoccupation scores. A Structural Equation Model showed that food preoccupation mediated the relationship between restraint and recall. In addition, restraint predicted enhanced visual memory but only in the later more difficult stages of a paired associated learning task. Further investigation is required to assess whether restrained eaters enhanced ability to recall eaten foods contributes to actual reductions in dietary intake.

Social norms influence food choice and intake and could be exploited to promote healthier eating. Here we test the effect of two types of social norm messages on consumption of fruit and vegetables (FV) in low and high consumers of fruit and vegetables. Young adults (n = 75) read a poster that either (1) stated that other young adults regularly eat FV (descriptive social norm) or (2) stated that other young adults approve of regularly eating FV (injunctive social norm) or (3) outlined the health benefits of eating FV (control condition). Shortly after reading the poster participants were offered a snack including FV. Choice and intake were measured covertly. In habitually low consumers of FV, fruit and vegetable selection and intake was higher after reading a descriptive norm poster than after reading about the health benefits of eating FV. However, participants viewing an injunctive norm poster ate a similar amount of FV as the participants in the health control condition. No effect of message type was observed in habitually high consumers of FV with habitual high consumers in all conditions selecting and eating a large amount of FV. These findings indicate that social norm messages emphasising behavioural norms may have more potential than injunctive norms in encouraging healthier eating. They further suggest that social normative information may not bring about behavioural change due to social approval concerns.

Alexithymia is defined as a deficit in the ability to understand and express emotion. There is a positive relationship between alexithymia and obesity but this relationship has yet to be investigated in adolescents. We predicted that adolescents with higher Body Mass Index (BMI) would have higher alexithymia scores. Nine schools in the Midlands region participated in data collection, which included objective measures of BMI, self-reported eating habits such as breakfast frequency and snacking behaviour and alexithymia. There were 60 male and 50 female participants, with a mean age of 12 (SD ± .7), mean alexithymia score of 33.7 (SD ± 4.9) and mean BMI of 20 (SD ± 4.7). Preliminary analysis indicated total alexithymia scores were not directly related to BMI and neither were any specific subscale scores. However, the subscale scores for Difficulty Describing Feelings were related to eating habits that contribute to overweight. For example, there was a negative relationship between Difficulty Describing Feelings scores and self-reported daily fruit and vegetable consumption, and a positive relationship between Difficulty Describing Feelings scores and unhealthy snacking. Alexithymia scores were not related to socioeconomic status or ethnicity. These results suggest that unhealthy eating habits may underlie the relationship between difficulties describing feelings and the emergence of obesity in adulthood.

While the concept of food addiction is highly controversial among the scientific community, lay acceptance is more widespread. Yet to date, nobody has compared the prevalence or predictors of self-perceived versus clinically diagnosed food addiction. In the present study, 303 university psychology students (89% female, age M = 19.3 SD = 1.5, BMI M = 21.7 SD = 2.7) were asked whether they thought they were addicted to any foods, and then completed the Yale Food Addiction Scale (YFAS) and other measures of eating pathology, dieting behaviour, body image, explicit and internalised weight stigma, and validation seeking personality traits. Only 6.9% of participants met the YFAS diagnostic criteria for food addiction; however, 51.5% of participants self-classified as food addicts. With the exception of explicit anti-fat bias, statistically significant differences on all measures were observed between participants classified as clinically diagnosed food addicts, self-perceived food addicts, and non-addicts. Self-perceived and clinical food addicts did not differ in the nature of substance dependence symptoms endorsed. Higher levels of dieting (59%) were reported in individuals meeting diagnostic criteria for food addiction than in self-perceived food addicts (20%) or non-addicts (11%). Although no differences in BMI were observed between those self-classifying as addicted or not, self-perceived food addiction was associated with higher scores on measures of eating pathology, body dissatisfaction, weight concerns, dieting behaviour and internalised weight stigma than in non-addicted participants. Self-perceived food addiction represents a significant and distinct population of subclinical eating pathology and may be a useful target for interventions aimed at reducing maladaptive eating behaviours.

The behavioural mechanisms underlying the effects of the opioid antagonist naloxone (0.3-3 mg/kg i.p.), and the opioid agonists morphine (0.3-3 mg/kg s.c.), and U-50, 488H (0.3-3 mg/kg s.c.) on ingestive behaviour were investigated using a microstructural analysis of licking patterns for sucrose solutions and Intralipid (fat emulsions) in a brief contact test. Naloxone dose-dependently decreased the total number of licks and the number of bouts for sucrose and Intralipid, but did not affect mean bout duration. Morphine dose-dependently increased the total number of licks and the number of bouts for both test fluids. For Intralipid but not for sucrose drinking, morphine actually decreased mean bout duration. U-50, 488H significantly affected total licks, although the dose-effect relationship showed an inverted U-shaped function. There was a dose-dependent increase in mean bout duration following administration of U-50, 488H and an increase in bout number, although only the lowest dose differed significantly from the control condition. The results show that microstructural analysis can distinguish between the effects of naloxone, morphine and U-50, 488H on licking behaviour and indicate that selective opioid receptor subtypes may be differentially involved in ingestive processes.

The neuroactive steroid 3α-hydroxy-5β-pregnan-20-one (pregnanolone) and benzodiazepine receptor (BZR) agonists share sedative, anxiolytic, and anticonvulsant properties. Recent evidence suggests that like BZR agonists, pregnanolone may also modulate feeding responses. The present experiments examined the behavioral mechanisms responsible for any hyperphagic effect of pregnanolone. The effect of pregnanolone (1–10 mg/kg IP) on the intake and microstructure of licking for two sucrose solutions (1 and 3%) in well familiarized nondeprived male rats under either light or dark conditions was examined. Pregnanolone had no effect on either intake or the duration or number of bouts of licking in these experiments, although in all cases the intrabout lick rate was significantly reduced at the highest dose. Pregnanolone (1–10 mg/kg) also failed to increase intake of a sweet wet mash in familiarized nondeprived male rats. However, in a food choice test where both novel and familiar food items were available, pregnanolone (1–3 mg/kg) significantly increased the time spent eating the novel food. These results suggest that unlike BZR agonists, which enhance feeding responses directly, pregnanolone may facilitate feeding secondarily via an attenuation of anxiety.

The role of endogenous opioid peptides in the effects of midazolam on ingestive behaviour was investigated using a detailed analysis of licking behaviour in the rat. Midazolam (1.8 mg/kg i.p.) was administered in combination with either flumazenil (10 and 20 mg/kg i.p.) or naloxone (0.1 and 0.3 mg/kg i.p.). The effect on licking patterns during 60-s exposures to a range of concentrations of a fat emulsion (Intralipid) was then recorded. Midazolam significantly increased the total number of licks for Intralipid by increasing the mean bout duration. This effect is consistent with the proposal that benzodiazepines enhance palatability. Flumazenil and naloxone were ineffective when administered alone, but both drugs blocked the effect of midazolam on total number of licks by selectively attenuating mean bout duration. Midazolam also produced a significant decrease in the intrabout lick rate, probably due to the muscle relaxant effects of this drug. This decrease in the intrabout lick rate was reversed by pretreatment with flumazenil but not by naloxone. The results suggest that endogenous opioids may be important for the palatability effects of midazolam, but may not be involved in the muscle relaxant effects of this drug.

BACKGROUND: Consumption of high calorie junk foods has increased recently, especially among young adults and higher intake may cause weight gain. There is a need to develop public health approaches to motivate people to reduce their intake of junk food. OBJECTIVE: To assess the effect of health and social norm messages on high calorie snack food intake (a type of junk food) as a function of usual intake of junk food. DESIGN: In a between-subjects design, 129 young adults (45 men and 84 women, mean age = 22.4 years, SD = 4.5) were assigned to one of three conditions: 1) a social norm condition, in which participants saw a message about the junk food eating habits of others; 2) a health condition, in which participants saw a message outlining the health benefits of reducing junk food consumption and; 3) a control condition, in which participants saw a non-food related message. After exposure to the poster messages, participants consumed a snack and the choice and amount of snack food consumed was examined covertly. We also examined whether usual intake of junk food moderated the effect of message type on high calorie snack food intake. RESULTS: The amount of high calorie snack food consumed was significantly lower in both the health and the social norm message condition compared with the control message condition (36% and 28%, both p

Benzodiazepine receptor agonists increase food intake in many different species, yet there has been little investigation of the central site of actions of these drugs on ingestive behaviour. In the present experiments, direct administration of the benzodiazepine receptor agonist midazolam (3-30 micrograms/microliter) into the parabrachial nucleus of the pons significantly increased the consumption of a wet mash diet and a 3% sucrose solution in adult non-deprived rats. The hyperphagic response was blocked by pre-treatment with the selective benzodiazepine receptor antagonist flumazenil. Injection of midazolam into the parabrachial nucleus had no effect on locomotor activity, despite the fact that in the same animals an increase in mash intake was observed following intra-parabrachial midazolam. These data suggest that benzodiazepine receptors located in the parabrachial nucleus may be an important site of action for the effects of benzodiazepines specifically on ingestive behaviour.

Social norms have been shown to influence food intake. Although social norms approaches have been adopted to reduce binge drinking, whether social normative information could be used to encourage ‘healthier’ food choices has not been examined. The present study investigated whether exposing participants to social norm messages about vegetable consumption increases choice and intake of vegetables as part of a meal. Sixty undergraduate students participated and were assigned to a social norms condition or a control condition. Dependent on condition, prior to selection of lunch from a buffet, participants were exposed to posters and flyers relating to social norms information about vegetables (‘students eat more vegetables than you’d think, the average student eats 3 portions of vegetables a day’) or health information about vegetables (‘eating vegetables is good for your health, eating 3 portions of vegetables a day protects against heart disease’). Cover stories were used to ensure participants were unaware the information exposure and food choice activities were related. Measures of habitual vegetable intake, BMI and restraint were taken after consumption of the lunch time meal. In habitually low consumers of vegetables, exposure to social norms information increased amount of vegetables consumed, compared to the control condition. In habitually high consumers of vegetables, no effect on vegetable intake was observed. These findings suggest a social norms approach to encourage ‘healthy’ food choices warrants further investigation.

Current commercial ice cream formulations vary greatly in both ingredients and price but few published studies have reported the effect of ice cream formulation on consumer responses. The aim of this study was to use a microstructural approach to examine eating behaviour and responses to two ice creams that differed in their microstructures and physical properties. Participants ate ice cream ad libitum in the laboratory, during which the amounts eaten were covertly recorded using the Sussex Eating Pattern Monitor (SIPM) and appetite and sensory ratings were taken. Participants consumed either a high fat or low fat ice cream that was presented without labels and they attended three test days to assess the possibility that learning about the properties of the ice cream might occur. There were no main effects of either ice cream or test day for any of the variables tested: sensory ratings, total intake, appetite and pleasantness ratings during the session. The results suggest that from a consumers perspective there is very little that separates ostensibly very different ice cream formulations on oral properties (taste and mouth feel) and that these assessments of consumers are not modified by learning over three days.

Exposure of satiated subjects to food related stimuli has been shown to decrease neural activation in areas involved in the control of eating behaviour. In the present study we investigated whether hunger or satiation affected BOLD fMRI responses to both rewarding and aversive visual and taste stimuli in healthy volunteers. Sixteen participants (8 male, 8 female) completed an fMRI task that has been used previously to assess the effects of serotonergic and dopaminergic drugs on reward processes. Participants were scanned before and after either eating to satiation or hungry (on separate test days); BOLD fMRI responses and subjective ratings, to the sight and/or taste of chocolate (rewarding) or the sight and/or taste of mouldy strawberries (aversive) were recorded. Analysis of VAS ratings of subjective pleasantness and wanting of the stimuli, suggests a dissociation between reward and aversion, as satiation attenuated responses to chocolate but not mouldy strawberries. The fMRI results showed differences in the BOLD response between the satiated and hungry conditions that were dependent on the nature of the stimuli (rewarding vs. aversive) in the following regions: orbital frontal cortex, insula, nucleus accumbens, caudate, putamen, hippocampus, amygdala and brainstem. The results provide a profile of satiation in a model of reward processing which may be of value in future studies to assess the mechanism of action of novel drugs to treat obesity and psychiatric disorders.

Impulsivity is related to a number of addictive behaviours, including drug and alcohol use. Individual differences in impulsivity may explain why some people are able to stick to long-term health goals whilst others are susceptible to temptation. In the modern food environment with an abundance of widely available tempting foods the ability to self-regulate is critical for successful control of eating behaviour. In this study, the relationship between the ability to delay gratification and eating behaviour is explored using a delay-discounting task. This task has been shown to demonstrate the extent to which individuals can inhibit immediate reward in pursuit of more adaptive delayed goals. Male and female participants were tested on a monetary delay-discounting task and a trail making task (measure of executive function) and completed a number of self-report measures of eating behaviour (Power of Food Scale, Dutch Eating Behaviour Questionnaire, Yale Food Addiction Scale) and impulsivity (BIS-11). Height, weight and dieting history were also recorded to get an accurate measure of BMI and current dieting status. Based on previous findings reported by Applehans et al. (2011; Obesity, 19, 2175–2182) we suggest that impulsivity and performance on the delay discounting task will predict eating style and we will explore the relationship between the ability to delay gratification and BMI. The results will be discussed in the context of the role of top-down processes in the cognitive control of eating.

Distraction while eating can enhance intake of afternoon snacks, perhaps due to the effects of distraction on meal memory. Here we test the hypothesis that greater engagement with a distracter (computer game) will be associated with poorer meal memory and enhanced afternoon snacking compared with either a low involvement distraction or a control condition with no distraction. Using a between subjects design, young women undergraduate students visited the laboratory to eat a fixed lunch while (1) playing a computer game for which they would win money (2) playing a computer without any incentive (3) alone in the absence of distraction. Intake of cookies at a tasting session later that afternoon was measured and participants recalled the order in which they ate lunch items and rated the memory for vividness. All participants ate all of the lunch and rated appetite during lunch did not differ according to condition. Participants ate significantly more cookies and had poorer serial recall of the lunch item order after they had eaten their lunch while playing the computer game for money than when they had eaten their lunch while playing the computer game without an incentive or without any distraction. Vividness of lunch memory was negatively correlated with cookie intake. These results suggest that there is a relationship between distraction at lunch and later food intake provide support for the idea that memory of the previous meal affects future consumption.

Caffeine is a well-known psychostimulant drug, capable of facilitating psychomotor and cognitive performance, improving mood and attenuating fatigue. Moreover, caffeine-related stimuli (e.g. smell and/or taste of coffee) have been associated with increases in physiological and subjective arousal and improvements in vigilance performance. These effects may have been due to classical conditioning but may also have been potentiated by expectancy due to the use of commonly consumed caffeinated beverages. The current study examined the role of classical conditioning, by examining whether a novel caffeine-paired context could acquire the ability to elicit caffeine-like facilitation on performance and mood. A differential conditioned paradigm was used in which one context was paired with caffeine ingestion (400 mg in a capsule) and a second context was paired with placebo. After four pairings in each condition, a test of conditioning was conducted in which placebo was administered in each context. The findings demonstrated significantly faster reaction time performance after placebo in the context previously paired with caffeine ingestion compared to the context previously paired with placebo. Furthermore, these conditioned effects were acquired quickly, after just two caffeine-context pairings and were acquired despite a reported absence of CS-US contingency awareness.

The importance of memory in appetite control has been appreciated for some time, but previous work has focused on the influence of memory for the predicted consequences of eating acquired over repeated experiences, e.g. as in associative conditioning of flavor preferences. In contrast, there has been little investigation of the role of episodic memory. We have examined whether manipulating memory for the specific attributes of foods eaten recently affects subsequent consumption. Enhancing memory for recent eating by cueing participants to recall their lunchtime meal suppressed snack intake later that afternoon relative to an uncued group. This effect of meal recall was specific to food eaten that day, because asking participants to remember lunch consumed the previous day had no effect on subsequent snack intake. We have further shown that cued-recall of lunch does not decrease snack intake at a session 1-h post-lunch but does decrease intake 3-h post-lunch (when some forgetting of the meal is likely to have occurred). The delay-dependency of the effect suggests it is a memory-related phenomenon. Furthermore, we found that disrupting memory for a recent meal by distracting participants at lunch led to an increase in afternoon snack consumption compared with a non-distracted group. These data are consistent with reports of multiple meal consumption in amnesic patients who are unable to remember having just eaten. It is concluded that representation in memory of information relating to foods that have been eaten in the recent past may have a role to play in controlling everyday eating.